When Osmund Bø Østensen was born on 14 February 1883, in Karmøy, Rogaland, Norway, his father, Osten Osmundsen, was 25 and his mother, Elen Karine Hansdatter, was 25. He married Josefine Kristine Sigvesdatter about 1909, in Karmøy, Rogaland, Norway. They were the parents of at least 3 sons and 2 daughters. He died on 22 September 1953, at the age of 70.